[libcamera-devel] [PATCH 1/2] simple-cam: Early return if no cameras found on the system

[Umang Jain]

Hi Kieran

On 9/24/20 8:11 PM, Kieran Bingham wrote:
> Hi Umang,
>
> On 24/09/2020 15:18, Umang Jain wrote:
>> Early return if no cameras are found on the system.
>> Failing to do so, the codepath will segfault while trying to
>> acquire a non-existent camera.
>>
> Ah, yes this sounds like a reasonably good idea to have here.
Great. I thought it was an overkill initially, but sent the patch anyway.
>> Signed-off-by: Umang Jain <email at uajain.com>
>> ---
>>   simple-cam.cpp | 7 +++++++
>>   1 file changed, 7 insertions(+)
>>
>> diff --git a/simple-cam.cpp b/simple-cam.cpp
>> index 3aa975e..d51000c 100644
>> --- a/simple-cam.cpp
>> +++ b/simple-cam.cpp
>> @@ -95,6 +95,13 @@ int main()
>>   	CameraManager *cm = new CameraManager();
>>   	cm->start();
>>   
>> +	if(!cm->cameras().size()) {
>> +		std::cout << "Please connect atleast one camera to the system."
> s/atleast/at least/
>
> Though I'd probably simply say "No cameras were identified on the
> system", as it might not always be feasible to 'add' a camera, and it
> might also be that the cameras are connected, but actually libcamera
> might not have the required pipelines enabled.
>
> So as the action to take is ambiguous, I'd leave it out and just state
> the facts.
Ah, indeed. I didn't put a lot of thought in writing the log message.
>
> Otherwise,
>
> Reviewed-by: Kieran Bingham <kieran.bingham at ideasonboard.com>
>
>> +			  << std::endl;
>> +		cm->stop();
>> +		return -1;
>> +	}
>> +
>>   	/*
>>   	 * Just as a test, list all id's of the Camera registered in the
>>   	 * system. They are indexed by name by the CameraManager.
>>